Narrator (April Hobart, CXC): Over four hundred years ago, the Danish astronomer Tycho Brahe studied the explosion of a star that later became known as Tycho's supernova. A look at Tycho in X-rays by NASA's Chandra X-ray Observatory shows that the supernova remnant contains an expanding bubble of superheated debris, which sits within an even more rapidly moving shell of extremely high-energy electrons. A very long Chandra observation of Tycho totaling about a million seconds of time, has uncovered new and unexpected structures in this aftermath of the star’s explosion. A series of stripes in the remnant provides novel evidence for particles that have been accelerated to extremely high energies. This is an important clue to better understanding the object that Tycho Brahe first saw back in 1572.